Thread (28 messages) 28 messages, 5 authors, 2011-03-11

Re: [PATCH v5 3/9] writeback: convert variables to unsigned

From: Minchan Kim <hidden>
Date: 2011-02-27 16:07:33
Also in: lkml

On Fri, Feb 25, 2011 at 01:35:54PM -0800, Greg Thelen wrote:
Convert two balance_dirty_pages() page counter variables (nr_reclaimable
and nr_writeback) from 'long' to 'unsigned long'.

These two variables are used to store results from global_page_state().
global_page_state() returns unsigned long and carefully sums per-cpu
counters explicitly avoiding returning a negative value.

Signed-off-by: Greg Thelen <redacted>
Reviewed-by: Minchan Kim <redacted>
quoted hunk ↗ jump to hunk
---
Changelog since v4:
- Created this patch for clarity.  Previously this patch was integrated within
  the "writeback: create dirty_info structure" patch.

 mm/page-writeback.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 2cb01f6..4408e54 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -478,8 +478,10 @@ unsigned long bdi_dirty_limit(struct backing_dev_info *bdi, unsigned long dirty)
 static void balance_dirty_pages(struct address_space *mapping,
 				unsigned long write_chunk)
 {
-	long nr_reclaimable, bdi_nr_reclaimable;
-	long nr_writeback, bdi_nr_writeback;
+	unsigned long nr_reclaimable;
+	long bdi_nr_reclaimable;
+	unsigned long nr_writeback;
+	long bdi_nr_writeback;
 	unsigned long background_thresh;
 	unsigned long dirty_thresh;
 	unsigned long bdi_thresh;
-- 
1.7.3.1
bdi_nr_[reclaimable|writeback] can return negative value?
When I just look through bdi_stat_sum, it uses *percpu_counter_sum_positive*.
So I guess it always returns positive value. 
If it is right, could you change it, too?

-- 
Kind regards,
Minchan Kim

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